Peel, halve, deseed and chop the cucumbers into 1cm cubes. Trim and quarter the radishes and combine these with the cucumber in a bowl. Heat the oil in a small frying pan over a medium heat and add the mustard and cumin seeds. Cook for 1 minute or until the seeds begin to pop. Add the chilli and cook for a further 30 seconds. Cool then pour the seed mixture over the cucumber and radishes. Add the remaining ingredients, salt to taste, then toss to combine. A great accompaniment to curry.